Hydrothermal Degradation of Brominated Epoxy Resin

It is generally accepted that degradation of epoxy resins starts by dehydration of secondary alcoholic groups followed by homolytic scission of the formed allylic bond [34, 35]. There have been various studies carried out for the brominated epoxy resin treatment. In the study of Balabanovich [33], brominated epoxy resin produces gases and oil as pyrolysis products at the temperature of about 100 °C. However, these pyrolysis volatiles are contaminated by brominated phenols, brominated alkanes, and HBr, which is a difficult point for pyrolysis of brominated epoxy resin. 

There are reports on the hydrothermal decomposition of condensation plastic model compounds as a prelude to study the reactions of real plastics. For example, compounds such as dinaphthylether and diphenylether [36], have been decomposed in the presence of basic additives to selectively obtain naphthol and phenol, respectively, indicating the chemical participation of water via hydrolysis. In the report of Brebu et al. [28], the alkaline hydrothermal treatment at 280 °C and autogenous pressure of 7 MPa were found to be effective for 80-90% debromination of HIPS-Br, obtaining a material chemically similar to polystyrene. And, Br can be recovered as KBr from aqueous solution after treatment, while plastic can be recovered as individual pellets with similar molecular weight as initial HIPS-Br. 

Referring to the treatment of waste PCBs containing brominated epoxy resin, hydro-thermal treatment was applied to recycle the nonmetallic materials. In the study, the waste PCBs were first pulverized by a high speed hammer mill. After screen separation. 

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